They could be used to explore caves and large areas. They have spinoff capabilities for helping the military to search caves and buildings.
An artists rendering of a microbot.
A swarm of microbots on Mars
Here is the project page at MIT
Hopping power is provided by a compliant bistable foot operated by Dielectric Elastomer Actuators
concept using 4 Dielectric Elastomer Actuators to change microbot orientation before hopping.